It is known to provide the stage of a concert hall or similar building with a sound shell, the sound shell providing reflecting surfaces which enhance the sound projected towards the audience area and reduce loss of sound in the direction of the back, sides and ceiling of the stage area. Such sound shells have also been found to improve the acoustic conditions in a performance area of the stage in a manner which enhances the way in which musicians in the performance area hear their own performance and the performances of other musicians and thereby tends to improve the quality of performance.
Typically in such indoor sound shells, reflective panels are supported by permanent structures around the stage and other reflectors above the stage or audience area may be supported from the roof of the building. Alternatively, sound shells have been proposed, as in U.S. Pat. No. 5,530,211, which are transportable and of modular construction so as to be readily erected and dismantled. Such temporary structures typically comprise reflecting panels on supporting towers.
When a performance is to take place in the open air, musicians may be provided either with a permanent or temporary stage structure which may provide a roof, rear wall and possibly side walls, but which invariably does not compare with the acoustic properties available to both musicians and audience within a concert hall having a stage with a stage with a sound shell. U.S. Pat. No. 4,278,145 proposes providing a concert shell for outdoor use and comprising a plurality of similarly constructed sections which can be erected and connected to form a shell, each section having an upright panel and a cantilevered upper section which can be tilted forwardly.